1. Field of the Invention
The present invention generally relates to protection circuitry and more particularly to a method and structure that includes a shunt device between the source/drain and gate of SOI transistors which may develop a voltage differential between the source/drain and gate during wafer fabrication. The shunt device eliminates the potential for charging damage from processing.
2. Description of Related Art
One problem that exists when designing integrated circuits with silicon-over-insulator (SOI) transistors relates to the detection of which SOI transistors may be susceptible to charging damage, and to providing protection once such a susceptible device is identified. In SOI it is not possible to “tie down” a floating gate in the traditional sense, such as by adding a diode connection to the substrate or nwell. SOI technologies are inherently less susceptible to charging damage because both the source/drain and the gate tend to have similar antennae, so the potential of both nodes varies together. This is not, however, certain in all cases. The invention described below is designed to detect and modify the integrated circuit design to eliminate the possibility of charging damage.